Maria Sharapova posted a letter to her fans Friday on her Facebook page, four days after the Russian tennis star said she failed a doping test at the Australian Open in January for the little-known meldonium.

The former world No. 1 took full responsibility for her mistake when she made the announcement at a news conference Monday in Los Angeles. The 28-year-old player could face a lengthy ban from the International Tennis Federation, possibly ending her season and preventing her from competing for Russia at the Rio Olympics.

Sharapova received notice last week that she tested positive for meldonium, a blood flow-promoting drug she has been taking for 10 years for numerous health issues. Meldonium was banned at the start of the year because it aids oxygen uptake and endurance, and several athletes across international sports have already been caught using it. Sharapova and all players were notified of the changes in the WADA banned substances list in December. Sharapova said she simply missed the change, neglecting to click on the link.

In the letter, Sharapova wrote:

To My Fans:

I want to reach out to you to share some information, discuss the latest news, and let you know that there have been things that have been reported wrong in the media, and I am determined to fight back. You have shown me a tremendous outpouring of support, and I'm so grateful for it. But I have also been aware that some not all, but some in the media distort, exaggerate and fail to accurately report the facts about what happened.

A report said that I had been warned five times about the upcoming ban on the medicine I was taking. That is not true and it never happened.

That's a distortion of the actual "communications," which were provided or simply posted onto a webpage.

I make no excuses for not knowing about the ban. I already told you about the December 22, 2015 email I received. Its subject line was "Main Changes to the Tennis Anti-Doping Programme for 2016." I should have paid more attention to it.

But the other "communications?" They were buried in newsletters, websites, or handouts.

On December 18, I received an email with the subject line "Player News" on it. It contained a newsletter on a website that contained tons of information about travel, upcoming tournaments, rankings, statistics, bulletin board notices, happy birthday wishes, and yes, anti-doping information. On that email, if a player wanted to find the specific facts about medicine added to the anti-doping list, it was necessary to open the "Player News" email, read through about a dozen unrelated links, find the "Player Zone" link, enter a password, enter a username, read a home screen with more than three dozen different links covering multiple topics, find the "2016 Changes to Tennis Anti-Doping Program and Information" link, click on it and then read a page with approximately three dozen more links covering multiple anti-doping matters. Then you had to click the correct link, open it up, scroll down to page two and that's where you would find a different name for the medication I was taking.

In other words, in order to be aware of this "warning," you had to open an email with a subject line having nothing to do with anti-doping, click on a webpage, enter a password, enter a username, hunt, click, hunt, click, hunt, click, scroll and read. I guess some in the media can call that a warning. I think most people would call it too hard to find.

There was also a "wallet card" distributed at various tournaments at the beginning of 2016, after the ban went into effect. This document had thousands of words on it, many of them technical, in small print. Should I have studied it? Yes. But if you saw this document (attached), you would know what I mean. Again, no excuses, but it's wrong to say I was warned five times.

There was also a headline that said, "4-6 Weeks Normal Treatment for Drug in Maria Sharapova Case." That headline has been repeated by many reporters who fail to tell their viewers and readers what the rest of the story says. The story quotes the manufacturer of my medicine as saying: "Treatment course can be repeated twice or thrice a year. Only physicians can follow and evaluate patient's health condition and state whether the patient should use meldonium for a longer period of time."

That's exactly what I did. I didn't take the medicine every day. I took it the way my doctor recommended I take it and I took it in the low doses recommended.

I'm proud of how I have played the game. I have been honest and upfront. I won't pretend to be injured so I can hide the truth about my testing.

I look forward to the ITF hearing at which time they will receive my detailed medical records. I hope I will be allowed to play again. But no matter what, I want you, my fans, to know the truth and have the facts.

— Maria